Linux: Discovery of Network Environment via Built-in Tools

Rule ID

PH_Rule_TH_EQLLIB_LINUX_4

Default Status

Enabled

Description

Detects the use of Build-in tools to enumerate and discover network environment on unix systems.

Severity

MITRE ATT&CK® Tactics

Discovery

Discovery consists of techniques an adversary may use to gain knowledge about the system and internal network. These techniques help adversaries observe the environment and orient themselves before deciding how to act. They also allow adversaries to explore what they can control and what’s around their entry point in order to discover how it could benefit their current objective. Native operating system tools are often used toward this post-compromise information-gathering objective.

https://attack.mitre.org/tactics/TA0007

MITRE ATT&CK® Techniques

T1016.001

System Network Configuration Discovery: Internet Connection Discovery

Adversaries may check for Internet connectivity on compromised systems. This may be performed during automated discovery and can be accomplished in numerous ways such as using [Ping](https://attack.mitre.org/software/S0097), tracert, and GET requests to websites.

https://attack.mitre.org/techniques/T1016/001

Impacts

Server

Data Source

Linux Process Monitoring via FortiSIEM Agent

Detection

Correlation

Remediation Guidance

No remediation guidance specified

Time Window

If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.

300 seconds

Trigger Conditions

If the following defined pattern/s occur within a 300 second time window.

Filter

SubPattern Definitions

SubPattern Name: Filter

This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.

SubPattern Query

This is the query logic that matches incoming events

eventType = "LINUX_PROCESS_EXEC" AND (procName IN ("arp","ifconfig","netstat","networkctl","ntop","route") OR (procName IN ("cat","gedit","less","more","nano","vi","vim") AND swParam CONTAIN " /etc/hosts"))

Group by Attributes

This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID

hostName,procName,swParam

Aggregate Constraint

This is most typically a numerical constraint that defines when the rule should trigger an incident

COUNT(*) >= 1

Incident Attribute Mapping

This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.

The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern

 hostName = Filter.hostName,
procName = Filter.procName,
swParam = Filter.swParam

FortiSIEM Rules